System and method for determining the information transfer rate between a driver and vehicle

ABSTRACT

A method and a system for determining an information transfer rate between a driver and a vehicle, where the information transfer rate is calculated using driver information measured directly from the driver and vehicle information measured directly from the vehicle. The method also includes retrieving a baseline information transfer rate for maintaining control of the vehicle from a baseline information transfer rate database. A driver safety factor is calculated using the information transfer rate and the baseline information transfer rate.

RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application Ser.No. 62/016,020, filed on Jun. 23, 2014, which is expressly incorporatedherein by reference.

BACKGROUND

A constant flow of information from a driver to a vehicle is required inorder for the driver to maintain control of the vehicle. The drivermaintains control of the vehicle, for example, by transmittinginformation to the vehicle through the steering wheel, accelerator andbrakes to produce appropriate changes in vehicle acceleration, velocity,lane position, and direction. A reduction in the flow of informationfrom the driver to the vehicle, such as due to driver impairment, canresult in a reduction or loss of vehicular control.

BRIEF DESCRIPTION

According to one aspect, a computer implemented method for determiningan information transfer rate between a driver and a vehicle includesmeasuring driver information directly from the driver, measuring vehicleinformation directly from the vehicle and calculating an informationtransfer rate between the driver and the vehicle using the driverinformation measured directly from the driver and the vehicleinformation measured directly from the vehicle. The method includesretrieving a baseline information transfer rate for maintaining controlof the vehicle from a baseline information transfer rate database, andcalculating a driver safety factor using the information transfer ratebetween the driver and the vehicle and the baseline information transferrate.

According to another aspect, a non-transitory computer-readable mediumstoring executable code for determining an information transfer ratebetween a driver and a vehicle is provided. The code, when executed,performs the steps of measuring driver information directly from thedriver, measuring vehicle information directly from the vehicle andcalculating an information transfer rate between the driver and thevehicle using the driver information measured directly from the driverand the vehicle information measured directly from the vehicle. Themethod includes retrieving a baseline information transfer rate formaintaining control of the vehicle from a baseline information transferrate database and calculating a driver safety factor using theinformation transfer rate between the driver and the vehicle and thebaseline information transfer rate.

According to yet another aspect, an information transfer rate system fordetermining an information transfer rate between a driver and a vehicleis provided. The system includes a computer processor and a computerreadable storage medium storing executable code. The code, when executedby the computer processor, performs the steps of measuring driverinformation directly from the driver using a driver information sensingdevice, measuring driver information directly from the vehicle using avehicle information sensing device of the vehicle, and calculating aninformation transfer rate between the driver and the vehicle using thedriver information measured directly from the driver and the vehicleinformation measured directly from the vehicle, wherein the informationtransfer rate is calculated using an information transfer rate module ofthe information transfer rate system. The method includes retrieving abaseline information transfer rate for maintaining control of thevehicle from a baseline information transfer rate database of theinformation transfer rate system, and calculating a driver safety factorusing the information transfer rate between the driver and the vehicleand the baseline information transfer rate, wherein the driver safetyfactor is calculated using a driver safety factor module of theinformation transfer rate system.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of a vehicle having an information transferrate system for determining the information transfer rate between adriver and vehicle according to an exemplary embodiment;

FIG. 2 is a schematic view of an information transfer rate system ofFIG. 1 for determining the information transfer rate between a driverand vehicle according to an exemplary embodiment;

FIG. 3 is a process flow diagram of a method for determining aninformation transfer rate between a driver and vehicle according to anexemplary embodiment;

FIG. 4 is a process flow diagram of a real time continuously repeatingmethod for determining an information transfer rate between a driver andvehicle according to an exemplary embodiment;

FIG. 5 is a process flow diagram of a method for determining anormalized information transfer rate between a driver and vehicleaccording to an exemplary embodiment; and

FIG. 6 is a process flow diagram of a method for determining aninformation transfer rate between a driver and vehicle using externalinformation according to an exemplary embodiment.

DETAILED DESCRIPTION

Embodiments are now described with reference to the figures where likereference numbers indicate identical or functionally similar elements.

Reference in the specification to “one embodiment” or to “an embodiment”means that a particular feature, structure, or characteristic describedin connection with the embodiments is included in at least oneembodiment. The appearances of the phrase “in one embodiment” or “anembodiment” in various places in the specification are not necessarilyall referring to the same embodiment.

A “bus”, as used herein, refers to an interconnected architecture thatis operably connected to other computer components inside a computer orbetween computers. The bus can transfer data between the computercomponents. The bus can be a memory bus, a memory controller, aperipheral bus, an external bus, a crossbar switch, and/or a local bus,among others. The bus can also be a vehicle bus that interconnectscomponents inside a vehicle using protocols such as Controller Areanetwork (CAN), Local Interconnect Network (LIN), among others.

A “processor”, as used herein, processes signals and performs generalcomputing and arithmetic functions. Signals processed by the processorcan include digital signals, data signals, computer instructions,processor instructions, messages, a bit, a bit stream, or other meansthat can be received, transmitted and/or detected. Generally, theprocessor can be a variety of various processors including multiplesingle and multicore processors and co-processors and other multiplesingle and multicore processor and co-processor architectures. Theprocessor can include various modules to execute various functions.

A “disk”, as used herein can be, for example, a magnetic disk drive, asolid state disk drive, a floppy disk drive, a tape drive, a Zip drive,a flash memory card, and/or a memory stick. Furthermore, the disk can bea CD-ROM (compact disk ROM), a CD recordable drive (CD-R drive), a CDrewritable drive (CD-RW drive), and/or a digital video ROM drive (DVDROM). The disk can store an operating system that controls or allocatesresources of a computing device.

A “memory”, as used herein can include volatile memory and/ornonvolatile memory. Non-volatile memory can include, for example, ROM(read only memory), PROM (programmable read only memory), EPROM(erasable PROM), and EEPROM (electrically erasable PROM). Volatilememory can include, for example, RAM (random access memory), synchronousRAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double datarate SDRAM (DDRSDRAM), and direct RAM bus RAM (DRRAM). The memory canstore an operating system that controls or allocates resources of acomputing device.

A “module”, as used herein, includes, but is not limited to, hardware,firmware, software in execution on a machine, and/or combinations ofeach to perform a function(s) or an action(s), and/or to cause afunction or action from another module, method, and/or system. A modulecan include a software controlled microprocessor, a discrete logiccircuit, an analog circuit, a digital circuit, a programmed logicdevice, a memory device containing executing instructions, and so on.

A “database”, as used herein can refer to table, a set of tables, a setof data stores and/or methods for accessing and/or manipulating thosedata stores.

An “output device” as used herein can include devices that can derivefrom vehicle components, systems, subsystems, and electronic devices.The term “output devices” includes, but is not limited to: displaydevices, and other devices for outputting information and functions.

A “vehicle”, as used herein, refers to any moving vehicle that iscapable of carrying one or more human occupants and is powered by anyform of energy. The term “vehicle” includes, but is not limited to:cars, trucks, vans, minivans, SUVs, motorcycles, scooters, boats,personal watercraft, and aircraft. In some cases, a motor vehicleincludes one or more engines.

A “vehicle system”, as used herein can include, but are not limited to,any automatic or manual systems that can be used to enhance the vehicle,driving and/or safety. Exemplary vehicle systems include, but are notlimited to: an electronic stability control system, an anti-lock brakesystem, a brake assist system, an automatic brake prefill system, a lowspeed follow system, a cruise control system, a collision warningsystem, a collision mitigation braking system, an auto cruise controlsystem, a lane departure warning system, a blind spot indicator system,a lane keep assist system, a navigation system, a transmission system,brake pedal systems, an electronic power steering system, visual devices(e.g., camera systems, proximity sensor systems), a climate controlsystem, an electronic pretensioning system, among others.

Some portions of the detailed description that follows are presented interms of algorithms and symbolic representations of operations on databits within a computer memory. These algorithmic descriptions andrepresentations are the means used by those skilled in the dataprocessing arts to most effectively convey the substance of their workto others skilled in the art. An algorithm is here, and generally,conceived to be a self-consistent sequence of steps (instructions)leading to a desired result. The steps are those requiring physicalmanipulations of physical quantities. Usually, though not necessarily,these quantities take the form of electrical, magnetic or opticalnon-transitory signals capable of being stored, transferred, combined,compared and otherwise manipulated. It is convenient at times,principally for reasons of common usage, to refer to these signals asbits, values, elements, symbols, characters, terms, numbers, or thelike. Furthermore, it is also convenient at times, to refer to certainarrangements of steps requiring physical manipulations or transformationof physical quantities or representations of physical quantities asmodules or code devices, without loss of generality.

However, all of these and similar terms are to be associated with theappropriate physical quantities and are merely convenient labels appliedto these quantities. Unless specifically stated otherwise as apparentfrom the following discussion, it is appreciated that throughout thedescription, discussions utilizing terms such as “processing” or“computing” or “calculating” or “determining” or “displaying” or“determining” or the like, refer to the action and processes of acomputer system, or similar electronic computing device (such as aspecific computing machine), that manipulates and transforms datarepresented as physical (electronic) quantities within the computersystem memories or registers or other such information storage,transmission or display devices.

Certain aspects of the embodiments described herein include processsteps and instructions described herein in the form of an algorithm. Itshould be noted that the process steps and instructions of theembodiments could be embodied in software, firmware or hardware, andwhen embodied in software, could be downloaded to reside on and beoperated from different platforms used by a variety of operatingsystems. The embodiments can also be in a computer program product whichcan be executed on a computing system.

The embodiments also relates to an apparatus for performing theoperations herein. This apparatus can be specially constructed for thepurposes, e.g., a specific computer, or it can comprise ageneral-purpose computer selectively activated or reconfigured by acomputer program stored in the computer. Such a computer program can bestored in a non-transitory computer readable storage medium, such as,but is not limited to, any type of disk including floppy disks, opticaldisks, CD-ROMs, magnetic-optical disks, read-only memories (ROMs),random access memories (RAMs), EPROMs, EEPROMs, magnetic or opticalcards, application specific integrated circuits (ASICs), or any type ofmedia suitable for storing electronic instructions, and each coupled toa computer system bus. Furthermore, the computers referred to in thespecification can include a single processor or can be architecturesemploying multiple processor designs for increased computing capability.

The algorithms and displays presented herein are not inherently relatedto any particular computer or other apparatus. Various general-purposesystems can also be used with programs in accordance with the teachingsherein, or it can prove convenient to construct more specializedapparatus to perform the method steps. The structure for a variety ofthese systems will appear from the description below. In addition, theembodiments are not described with reference to any particularprogramming language. It will be appreciated that a variety ofprogramming languages can be used to implement the teachings of theembodiments as described herein, and any references below to specificlanguages are provided for disclosure of enablement and best mode of theembodiments.

In addition, the language used in the specification has been principallyselected for readability and instructional purposes, and may not havebeen selected to delineate or circumscribe the inventive subject matter.Accordingly, the disclosure of the embodiments is intended to beillustrative, but not limiting, of the scope of the embodiments, whichis set forth in the claims.

System Overview

Referring now to the drawings, wherein the showings are for purposes ofillustrating one or more exemplary embodiments and not for purposes oflimiting same, in FIG. 1, there is shown a schematic view of a vehicle500 having an information transfer rate system 535 for determining theinformation transfer rate between a driver 545 and vehicle 500 accordingto an exemplary embodiment. In one embodiment, the vehicle 500 comprisesa driver information sensing device 505, a vehicle information sensingdevice 510, an information transfer rate system 535, a driver alertdevice 540, a GPS 530, and optionally an external information sensingdevice 520. Note that the vehicle 500 can include components other thanthose illustrated in FIG. 1 and further note that some components of avehicle 500 such as the engine, tires, and suspension are omitted forbrevity purposes.

Controlling a vehicle 500 requires a constant flow of information fromthe driver 545 to the vehicle 500 in accordance with road and trafficconditions. To control the vehicle 500, the driver 545 must transmitinformation by way of one or more driver control input devices toproduce appropriate changes in vehicle acceleration, velocity, laneposition, and direction. Driver control input devices (not shown)include, but are not limited to, a steering wheel, accelerator pedal,and brake pedal. Thus, a reduction in information transfer from thedriver 545 to the vehicle 500 can signal a reduction in vehicularcontrol, as could be the case with a driver 545 who is distracted,drowsy, intoxicated or experiencing a medical emergency.

In one embodiment, the driver information sensing device 505 can measuredriver information directly from the driver 545, such as biometric dataand direct driver control input device data. Driver biometric data caninclude one or more types of driver biometric data, including, but notlimited to, eyelid aperture, pupil diameter, head position, gazedirection, eye blink rate, respiratory rate, heart rate, hand position,aortic blood flow, leg position, and brain electrical activity. Directdriver control input device data can include data from one or more typesof driver control input devices, such as, but not limited to, thesteering wheel, brake pedal, and gas pedal of vehicle 500. Accordingly,the direct driver control input device data, can include, but is notlimited to, one or more of the position of the vehicle steering wheel,turn velocity of the steering wheel, turn acceleration of the steeringwheel, position of the vehicle gas pedal, velocity of the gas pedal,acceleration of the gas pedal, position of the vehicle brake pedal,velocity of the brake pedal, and acceleration of the brake pedal.

It is contemplated that in some embodiments, one driver informationsensing device 505 can be used to measure one or more types of driverinformation directly from the driver 545. In other embodiments, multipledriver information sensing devices 505 can be used to measure multipletypes of driver information directly from the driver 545. For example,in one embodiment, driver information sensing device 505 can include anelectroencephalograph for measuring the driver brain electricalactivity. In another embodiment, one driver information sensing device505 can include a camera for measuring the driver eyelid aperture, thegas pedal for measuring the position of the vehicle gas pedal, and thebrake pedal for measuring the position of the vehicle brake pedal, andso forth.

Further, in other embodiments, the driver information sensing device 505can be a camera for measuring the driver eyelid aperture, another driverinformation sensing device 505 can be a driver control input device,such as the vehicle gas pedal, or a component of the gas pedal, formeasuring the position of the gas pedal, and an additional driverinformation sensing device 505 can be another driver control inputdevice, such as the vehicle brake pedal, or a component of the brakepedal, for measuring the position of the brake pedal. In otherembodiments, driver information sensing device 505 can be comprised ofone or more of a contact and/or contactless sensors and can includeelectric current/potential sensors (e.g., proximity, inductive,capacitive, electrostatic), subsonic, sonic, and ultrasonic sensors,vibration sensors (e.g., piezoelectric) visual, photoelectric, oxygensensors, as well as any other kinds of devices, sensors, or systems thatare capable of measuring driver information directly from the driver545.

In one embodiment, the vehicle information sensing device 510 canmeasure vehicle information directly from a vehicle system of vehicle500. For example, the vehicle information sensing device 510 can measurevehicle information directly from the vehicle 500, such as the laneposition, lane deviation, linear and angular vehicle position, velocityand acceleration, distance from potential obstacles in front of, besideand behind the vehicle 500, reliance on cruise control, reliance onassisted steering and reaction to known obstacles, such as constructionbarricades, traffic signals, and stopped vehicles.

As with the driver information sensing device 505, in some embodiments,one vehicle information sensing device 510 can be used to measure one ormore types of vehicle information directly from the vehicle 500. Inother embodiments, multiple vehicle information sensing devices 510 canbe used to measure multiple types of vehicle information. For example,in one embodiment, the vehicle information sensing device 510 caninclude a camera for measuring lane position of the vehicle 500 and anaccelerometer for measuring the acceleration of the vehicle 500. Infurther embodiments, the vehicle information sensing device 510 can be acamera for measuring lane position of the vehicle 500, another vehicleinformation sensing device 510 of the vehicle 500 can be anaccelerometer for measuring the acceleration of the vehicle 500, and athird vehicle information sensing device 510 can be an ultrasonicdetector for measuring the distance from the vehicle 500 to anypotential obstacles located around the vehicle 500.

The driver alert device 540 is used to alert the driver 545 if areduction in vehicle control occurs, namely if the driver safety factor,discussed below, does not exceed a predetermined driver safety alertthreshold, discussed below, due to a low information transfer ratebetween the driver 545 and the vehicle 500. The driver alert device 540can be an output device of the vehicle 500 that outputs a visual,mechanical, or audio signal to alert the driver 545 to the reduction invehicle control, which would allow the driver 545 to take action, suchas pulling the vehicle 500 over, stopping the vehicle 500, or swervingthe vehicle 500.

The external information sensing device 520 can be used to measureinformation external to the vehicle 500, and thus the flow ofinformation from the driver 545 to the vehicle 500 in reaction to theexternal information. The external information sensing device 520 canmeasure external information, such as, but not limited to, adjacentvehicles, road construction barricades, stopped traffic, animals, andpedestrians. It is contemplated that in some embodiments, one externalinformation sensing device 520 can be used to measure one or more typesof external information. In other embodiments, multiple externalinformation sensing devices 520 can be used to measure multiple types ofexternal information. For example, in one embodiment, the externalinformation sensing device 520 can include a camera to sense an animalexternal to the vehicle 500, an inter-vehicular communication system forsensing other vehicles adjacent to the vehicle 500, and an ultrasonicproximity sensor for sensing objects near the vehicle 500. In anotherembodiment, one external information sensing device 520 can include acamera to sense an animal external to the vehicle 500, another externalinformation system can include an inter-vehicular communication systemfor sensing other vehicles adjacent to the vehicle 500, and anotherexternal information system can include an ultrasonic proximity sensorfor sensing objects near the vehicle 500.

The GPS 530 can optionally be present in the vehicle 500 and can be usedto obtain the location, weather, and time of day traffic conditions atthe location of the vehicle 500 for use during the normalization processof the information transfer rate between the driver 545 and the vehicle500, in embodiments of the information transfer rate system 535, whichnormalize such information. It is recognized that normalizing theinformation transfer rate between the driver 545 and the vehicle 500 canbe necessary due to the fact that a higher information transfer rate isrequired to maintain control of vehicle 500 in some driving conditionsand a lower information transfer rate is required to maintain control ofthe vehicle 500 in other driving conditions. For example, curvy innercity roads during rush hour on snowy days require a higher informationtransfer rate from the driver 545 to the vehicle 500 to maintain controlof the vehicle 500, than will long straight desolate roads in fairweather.

Turning now to FIG. 2, there is shown a schematic detailed view of aninformation transfer rate system 535 for determining the informationtransfer rate between a driver 545 and vehicle 500 according to anexemplary embodiment, which will be described with reference to theelements of FIG. 1. The information transfer rate system 535 comprises acomputer processor 601 and a memory 605. Note that the informationtransfer rate system 535 comprises features, such as communicationinterfaces to the driver information sensing device 505, vehicleinformation sensing device 510, driver alert device 540, GPS 530, andoptional external information sensing device 520 (FIG. 1). However,illustration of these features has been omitted for brevity purposes.Note that in other embodiments, the information transfer rate system 535can also comprise additional features other than those illustrated inFIGS. 1 and 2.

In one embodiment, the processor 601 processes data signals and cancomprise various computing architectures including a complex instructionset computer (CISC) architecture, a reduced instruction set computer(RISC) architecture, or an architecture implementing a combination ofinstruction sets. Although only a single processor is shown in FIG. 2,multiple processors can be included. The processor 601 can comprise anarithmetic logic device, a microprocessor, a general purpose computer,or some other information appliance equipped to transmit, receive, andprocess non-transitory electronic data signals from the memory 605, thedriver information sensor device 505, the vehicle information sensingdevice 510, the driver alert device 540, the GPS 530, and the externalinformation sensing device 520.

In one embodiment, the memory 605 stores instructions and/or data thatcan be executed by the processor 601. The instructions and/or data cancomprise code (i.e. modules) for performing and and/or all of thetechniques described herein. In one embodiment, the memory 605 comprisesa baseline information transfer rate database 610, a driver alert module615, an information transfer rate module 620, and a driver safety factormodule 625. Note that in other embodiments, other modules than thoseshown in FIG. 2 can be used to perform the functionality describedherein. The modules are adapted to communicate, via a bus (not shown),with the processor 601, the driver information sensing device 505, thevehicle information sensing device 510, the driver alert device 540, theGPS 530, and the optional external information sensing device 520.

In one embodiment, the information transfer rate module 620 receivesdriver information measured directly from the driver 545 from the driverinformation sensing device 505 in the form of a driver time seriescalculated according to the following equation:D _(x) ={d _(x1) ,d _(x2) . . . d _(xN)}  (1)where: D_(x) is a time series which is an ordered collection of realvalues of driver information measured directly from the driver 545 usingthe driver information sensing device 505, and d_(x) is a time seriessegment of a real value of driver information measured directly from thedriver 545 using the driver information sensing device 505.

Further, the information transfer rate module 620 receives vehicleinformation measured directly from the vehicle 500 from the vehicleinformation sensing device 510 in the form of a vehicle time seriescalculated according to the following equation:V _(y) ={v _(y1) ,v _(y2) . . . v _(yN)}  (2)where: V_(y) is a time series which is an ordered collection of realvalues of vehicle information measured directly from the vehicle usingthe vehicle information sensing device 510, and v_(y) is a time seriessegment of a real value of vehicle information measured directly fromthe vehicle using the vehicle information sensing device 510.

The information transfer rate module 620 calculates an informationtransfer rate between the driver and vehicle using the vehicleinformation measured directly from the vehicle 500 by the vehicleinformation sensing device 510 and the driver information measureddirectly from the driver 545 by the driver information sensing device505. The information transfer rate between the driver 545 and thevehicle 500 is calculated using conditional and transfer entropies.Conditional entropy quantifies the amount of information needed todescribe the outcome of a random variable Y given that the value ofanother random variable X is known. Further, transfer entropy is anon-parametric statistic measuring the amount of directed(time-asymmetric) transfer of information between two random processes.Transfer entropy from a process X to another process Y is the amount ofuncertainty reduced in future values of Y by knowing the past values ofX given past values of Y. Thus, in one embodiment, the informationtransfer rate system 535 measures the reduction in uncertainty in V(vehicle) given historical segments of both V and D (driver) withrespect to the reduction of uncertainty in V given only historicalsegments of V. In other words, the information transfer rate system 535ascertains how much knowing D assists with determining V.

More specifically, in one embodiment, the information transfer ratebetween the driver 545 and the vehicle 500 is calculated according tothe following equation:T _(D) _(x) _(→V) _(y) =H(v _(yi) |v _(y(i-t)) ^((l)))−H(v _(yi) |v_(y(i-t)) ^((l)) ,d _(x(i-τ)) ^((k)))  (3)where: T_(D) _(x) _(→V) _(y) is a transfer entropy from a drivermeasurement x to a vehicle measurement y, H(v_(yi)|v_(y(i-t)) ^((l))) isthe conditional entropy between v_(yi) and a prior segment of V_(y) thatis l points long and delayed by t points i.e. v_(y(i-t))^((l))={v_(y(i-t-l+1)), v_(y(i-t-l+2)), . . . , v_(y(i-t))}, andH(v_(yi)|v_(y(i-t)) ^((l)), d_(x(i-τ)) ^((k))) is the conditionalentropy between v_(i) and a prior segment of V_(y) further conditionedon a prior segment of D_(x) that is k points long and delayed by τ timepoints i.e. d_(x(i-τ)) ^((k))={d_(x(i-τ-k+1)), d_(x(i-τ-k+2)), . . . ,d_(x(i-τ))}. Note that further conditioning of v_(yi) on d_(x(i-τ))^((k)) cannot increase the uncertainty in v_(i) so H(v_(yi)|v_(y(i-t))^((l)))≧H(v_(yi)|v_(y(i-t)) ^((l))), d_(x(i-τ)) ^((k))) and T_(D) _(x)_(→V) _(y) is always greater than zero.

The information transfer rate module 620 can be configured to use all ofthe driver information and vehicle information separately or incombination to form various transfer information sums and calculate aninformation transfer rate between the driver and vehicle. For example,in one embodiment, a total information transfer T_(D→V) is calculated bythe information transfer rate module 620 using the following equation:T _(D→V)=Σ_(x=1) ^(X)Σ_(y=1) ^(Y) H(v _(yi) |v _(y(i-t)) ^((l)))−H(v_(yi) |v _(y(i-t)) ^((l)) ,d _(x(i-τ)) ^((k)))  (4)which is the total sum over every possible combination of all driverinformation measured directly from the driver 545 (X in total) by thedriver information sensing device 505 and all vehicle measurementsmeasured directly from the vehicle (Y in total) by the vehicleinformation sensing device 510 for a total of X*Y individual sums.

In other embodiments, the information transfer rate module 620 can beconfigured to use only some of the driver information and vehicleinformation separately or in combination to form various transferinformation sums and calculate an information transfer rate between thedriver and vehicle. For example, in one embodiment, a sum of thecombinations of driver information measurements 3 through 5 measureddirectly from the driver 545 by the driver information sensing device505 and vehicle measurements 2 through 6 measured directly from thevehicle 500 by the vehicle information sensing device 510, representedas T_(D) ₃₋₅ _(→V) ₂₋₆ , can be calculated by the information transfermodule 620 using the following equation:T _(D) ₃₋₅ _(→V) ₂₋₆ =Σ_(x=3) ⁵Σ_(y=2) ⁶ H(v _(yi) |v _(y(i-t))^((l)))−H(v _(yi) |v _(y(i-t)) ^((l)) ,d _(x(i-τ)) ^((k))).  (5)

Thus, as can be seen, the information transfer rate between the driver545 and the vehicle 500 is calculated by the information transfer ratemodule 620 using entropy. More specifically, the transfer rate iscalculated by information transfer rate module 620, using transferentropy and conditional entropy. Each of equations 3-5, discussed above,provide an information transfer rate between the driver 545 and thevehicle 500 using transfer entropy and conditional entropy.

In some embodiments, information transfer rate module 620 also uses theexternal measurements, measurements of information external to thevehicle 500, provided by external information sensing device 520 tocalculate the information transfer rate between the driver and vehicle.

In some embodiments, the information transfer rate module 620 normalizesthe calculated information transfer rate based on at least one of thetype of driver information measured directly from the driver 545 and thedriving conditions. The driving conditions include at least one of aparticular road condition, weather condition, time of day, and trafficcondition. Further, in some embodiments, the information transfer ratemodule 620 also uses the information provided by the GPS 530 of thevehicle 500 to normalize the information transfer rate for the drivingconditions. In one embodiment, the information transfer rate module 620determines the maximum information transfer rate by adjusting theparameters t, τ, k, l of the above discussed equations to determine themaximum information transfer rate between the driver 545 and the vehicle500. Specifically, in one embodiment, the parameters t, τ, k, l areadjusted based on at least one of a type of driver information measureddirectly from the driver 545 and the driving conditions. The drivingconditions include at least one of a particular road condition, aweather condition, a time of day, and a traffic condition.

In some embodiments, the information transfer rates between the driverand vehicle for all driver measurements and all vehicle measurements arecalculated by the information transfer rate module 620, tracked by theprocessor 601, and stored in the memory 605 to establish personalnormatives for each driver 545 of the vehicle 500. These personalnormatives are then stored in the baseline information transfer ratedatabase 610 as baseline information transfer rate values for the driver545, for retrieval and use by the driver safety factor module 625.

In one embodiment, the baseline information transfer rate database 610contains baseline information transfer rate values for maintainingcontrol of the vehicle 500. In some embodiments, the baselineinformation transfer rate database 610 only contains one baselineinformation transfer rate value. In other embodiments, the baselineinformation transfer rate database 610 contains at least two differentbaseline information transfer rate values for the driver 545, with eachvalue adjusted for road conditions. Road conditions can include, but arenot limited to, one or more of type of road, weather, time of day, andtraffic conditions.

In one embodiment, the driver safety factor module 625 calculates adriver safety factor for the driver 545 of the vehicle 500 in real time.The driver safety factor is the ratio of the rate of informationtransfer between the driver and vehicle calculated by the informationtransfer rate module 620 and the baseline information transfer rateretrieved from the baseline information transfer rate database 610 bythe driver safety factor module 625. In the event that baselineinformation transfer rate database 610 contains multiple baselineinformation transfer rates for the driver 545 of vehicle 500, the driversafety factor module 625 retrieves the baseline information transferrate that most closely matches the real time road conditions for theroad on which the vehicle 500 is travelling.

In one embodiment, the driver alert module 615 compares the driversafety factor calculated by the driver safety factor module 625 to apredetermined driver safety alert threshold. In the event that thecalculated driver safety factor does not exceed the predetermined driversafety alert threshold, an alert is issued to the driver 545 using thedriver alert device 540, as discussed above. The alert signals to thedriver 545 that the real time information transfer rate between thedriver and vehicle has fallen below the information transfer ratenecessary for the driver 545 to maintain suitable control of the vehicle500 given the present road conditions.

With additional reference to FIG. 2, the information transfer ratesystem 535 can include the processor 601 and the memory 605. The system535 can further include the baseline information transfer rate database610, the driver alert module 615, the information transfer rate module620, and the driver safety factor module, each of which can be stored inthe memory 605. The baseline information transfer rate database 610 caninclude baseline information transfer rates between the driver 545 andthe vehicle 500 that are necessary for control of the vehicle 500 undera given set of road conditions. The information transfer rate module 620calculates the actual information transfer rate between the driver 545and the vehicle 500 using the information transfer rate module 620. Theinformation transfer rate module 620 also compares the baseline rate forthe real time conditions of the vehicle 500 to the actual informationtransfer rate between the driver 545 and the vehicle 500 in real time.From this comparison, it can be determined if a driver 545 is insuitable control of the vehicle 500.

The driver safety factor module 625 can calculate a real time driversafety factor, which is the ratio of the calculated rate of informationtransfer to a predetermined information transfer rate. The driver alertmodule 615 compares the calculated real time driver safety factor to apredetermined driver safety alert threshold. The driver alert module 615provides an alert to the driver 545 if the calculated real time driversafety factor is low. A calculated real time driver safety factor is lowif the calculated real time driver safety factor does not exceed thepredetermined driver safety alert threshold, when the comparison isperformed by the driver alert module 615. The driver alert module 615alerts the driver 545, using the driver alert device 540, when thecalculated real time driver safety factor is low, thereby alerting tothe presence of an impaired driver 545.

With reference to FIG. 3, a process flow diagram of a method 100 fordetermining an information transfer rate between a driver 545 and avehicle 500 according to an exemplary embodiment is shown. The method ofFIG. 3 will be described with reference to FIGS. 1 and 2, though themethod of FIG. 3 can also be used with other systems and embodiments.

In step 101 of FIG. 3, driver information is measured directly from thedriver 545. In one embodiment, this driver information is measured usingthe driver information sensing device 505, as described above. In step105, vehicle information is measured directly from the vehicle 500. Inone embodiment, this vehicle information is measured using the vehicleinformation sensing device 510, as described above.

In step 110, an information transfer rate between the driver 545 and thevehicle 500 is calculated using the driver information measured directlyfrom the driver 545 in step 101 and the vehicle information measureddirectly from the vehicle in step 105. In one embodiment, thisinformation transfer rate is calculated using the information transferrate module 620, as described above. Thus, as can be seen, theinformation transfer rate between the driver 545 and the vehicle 500 iscalculated using entropy. More specifically, in some embodiments, thetransfer rate is calculated, using transfer entropy and conditionalentropy, as is shown above in each of equations 3-5.

At step 115, a baseline information transfer rate is retrieved from thebaseline information transfer rate database 610 by the driver safetyfactor module 625. As was stated above, in one embodiment, the baselineinformation transfer rate database 610 contains baseline informationtransfer rate values for maintaining vehicular control. In someembodiments, the baseline information transfer rate database 610 onlycontains one baseline information transfer rate value. In otherembodiments, the baseline information transfer rate database 610contains at least two different baseline information transfer ratevalues for the driver 545, with each value adjusted for road conditions.Road conditions can include, but are not limited to, one or more of typeof road, weather, time of day, and traffic conditions. In the event thatthe baseline information transfer rate database 610 has multipleinformation transfer rates for the driver 545 of vehicle 500, the driversafety factor module 625 retrieves the baseline information transferrate that most closely matches the real time road conditions for theroad on which the vehicle 500 is travelling.

In step 120, once the baseline information transfer rate is retrievedfrom the baseline information transfer rate database 610, a driver alertmodule 615 is armed. Information transfer rate system 535 arms driveralert module 615 after a baseline information transfer rate is retrievedfrom the baseline information transfer database 610 by the driver safetyfactor module. Upon arming, driver alert module 615 is prepared tocompare a predetermined driver safety alert threshold, stored in memory605, to the driver safety factor calculated by the driver safety factormodule 625. Driver alert module 615 performs the comparison when thedriver safety factor calculated by the driver safety factor module 625is provided to the driver alert module 615 by driver safety factormodule 625.

At step 125, a driver safety factor is calculated. In one embodiment,the driver safety factor is the ratio of the calculated rate ofinformation transfer to a predetermined information transfer rate. Inone embodiment, the driver safety factor is calculated by the driversafety factor module 625, as described above, using the informationtransfer rate calculated in step 110 and the baseline informationtransfer rate retrieved from the baseline information transfer ratedatabase 610 in step 115.

In step 130, the driver safety factor calculated in step 125 is comparedto a predetermined driver safety alert threshold. In one embodiment,this comparison is performed by the driver alert module 615, asdescribed above. In step 135, the driver 545 is alerted if the driversafety factor value does not exceed the predetermined driver safetyalert threshold value. The driver safety factor and predetermined driversafety alert threshold data type can be, but is not limited to, numeric,non-numeric, discrete, or continuous. In one embodiment, if thecomparison made by the driver alert module 615 in step 130 indicatesthat the driver safety factor does not exceed the predetermined driversafety alert threshold, then the driver 545 is alerted using the driveralert device 540, as described above.

With reference to FIG. 4, a process flow diagram of a method 100 fordetermining an information transfer rate between a driver 545 and avehicle 500 according to an exemplary embodiment is shown. The method ofFIG. 4 will be described with reference to FIGS. 1, 2 and 3, though themethod of FIG. 4 can also be used with other systems and embodiments.FIG. 4 contains additional steps beyond those shown in FIG. 3, namelysteps 140 to 155, which clearly show how this method is continuouslyrepeated in real time by the information transfer rate system 535 whilethe vehicle 500 is travelling.

In the embodiment shown in FIG. 4, after step 135, driver information isagain measured directly from the driver 545 in step 140. In oneembodiment, this driver information is measured using the driverinformation sensing device 505, as described above. Following step 140,vehicle information is measured directly from the vehicle 500 again instep 145. In one embodiment, this vehicle information is measured usingthe vehicle information sensing device 510, as described above.

In step 150, an information transfer rate between the driver 545 and thevehicle 500 is again calculated using the driver information measureddirectly from the driver 545 in step 140 and the vehicle informationmeasured directly from the vehicle 500 in step 145. In one embodiment,this information transfer rate is calculated using the informationtransfer rate module 620, as described above.

Following step 150, a baseline information transfer rate is once againretrieved from the baseline information transfer rate database 610 andprovided to the driver safety factor module 625 in step 155, asdescribed above. As was stated above, in one embodiment, the baselineinformation transfer rate database 610 contains baseline informationtransfer rate values for maintaining vehicular control. In someembodiments, the baseline information transfer rate database 610 onlycontains one baseline information transfer rate value. In otherembodiments, the baseline information transfer rate database 610contains at least two different baseline information transfer ratevalues for the driver 545, with each value adjusted for road conditions.Road conditions can include, but are not limited to, one or more of typeof road, weather, time of day, and traffic conditions. In the event thatthe baseline information transfer rate database 610 has multipleinformation transfer rates for the driver 545 of the vehicle 500, thedriver safety factor module 625 retrieves the baseline informationtransfer rate that most closely matches the real time road conditionsfor the road on which the vehicle 500 is travelling.

After the baseline information transfer rate is retrieved from thebaseline information transfer rate database 610 and provided to thedriver safety factor module 625 in step 155, the method returns to step125.

With reference to FIG. 5, a process flow diagram of a method 100 fordetermining an information transfer rate between a driver 545 and avehicle 500 according to an exemplary embodiment is shown. The method ofFIG. 5 will be described with reference to FIGS. 1, 2, 3, and 4 thoughthe method of FIG. 5 can also be used with other systems andembodiments. FIG. 5 contains additional steps beyond those shown inFIGS. 3 and 4, namely steps 111 and 151.

In the embodiment shown in FIG. 5, the information transfer rate betweenthe driver 545 and vehicle 500 calculated in step 110 by informationtransfer rate module 620 is normalized in step 111 by the informationtransfer rate module 620, as was discussed above, based on at least oneof a type of driver information measured directly from the driver 545and the driving conditions. The driving conditions include, but are notlimited to, at least one of a particular road condition, a weathercondition, a time of day, and a traffic condition. Further, in someembodiments, the information transfer rate module 620 also uses theinformation provided by the GPS 530 of the vehicle 500 to normalize theinformation transfer rate for the driving conditions.

Similarly, in step 151 of FIG. 5, the information transfer rate betweenthe driver 545 and vehicle 500 calculated in step 150 by informationtransfer rate module 620 is normalized in step 151 by informationtransfer rate module 620, as was discussed above, based on at least oneof a type of driver information measured directly from the driver 545and the driving conditions. The driving conditions include, but are notlimited to, at least one of a particular road condition, a weathercondition, a time of day, and a traffic condition. Further, in someembodiments, the information transfer rate module 620 also uses theinformation provided by the GPS 530 of the vehicle 500 to normalize theinformation transfer rate for the driving conditions.

With reference to FIG. 6, a process flow diagram of a method 100 fordetermining an information transfer rate between a driver 545 and avehicle 500 according to an exemplary embodiment is shown. The method ofFIG. 6 will be described with reference to FIGS. 1, 2, 3, 4, and 5though the method of FIG. 6 can also be used with other systems andembodiments. FIG. 6 contains additional steps beyond those of theembodiments of the method 100 shown in FIGS. 3-5, namely steps 106 and146. Note that in other embodiments, other steps can be performed thanthose illustrated in FIG. 6.

In step 106, external information is measured external of the vehicle500. In one embodiment, this external information is measured using theexternal information sensing device 520, as described above. Thisexternal information is used by the information transfer rate module 620in step 110, in conjunction with the driver information measured in step101 and the vehicle information measured in step 105, to calculate aninformation transfer rate between the driver 545 and vehicle 500 in step110, as described above.

Similarly, in step 146, external information is measured external of thevehicle 500. In one embodiment, this external information is measuredusing the external information sensing device 520, as described above.This external information is used by the information transfer ratemodule 620 in step 150, in conjunction with the driver informationmeasured in step 140 and vehicle information measured in step 145, tocalculate an information transfer rate between the driver 545 andvehicle 500 in step 150, as described above.

Thus, disclosed above are embodiments of a system and method forcalculating the information transfer rate between the driver 545 and thevehicle 500 by information transfer module 620 using informationmeasured directly from the driver 545 and information measured directlyfrom the vehicle 500. The information transfer rate is calculated inreal time using conditional and transfer entropies. The calculatedinformation transfer rate is used to determine if the driver 545 ofvehicle 500 is in suitable control of vehicle 500 or the driver 545 isexperiencing an impairment that prevents the driver 545 from havingsuitable control of vehicle 500.

It will be appreciated that various implementations of theabove-disclosed and other features and functions, or alternatives orvarieties thereof, can be desirably combined into many other differentsystems or applications. Also that various presently unforeseen orunanticipated alternatives, modifications, variations or improvementstherein can be subsequently made by those skilled in the art which arealso intended to be encompassed by the following claims.

The invention claimed is:
 1. A computer implemented method fordetermining an information transfer rate between a driver and a vehicle,the method comprising: measuring driver information directly from thedriver; measuring vehicle information directly from the vehicle;calculating an information transfer rate between the driver and thevehicle using the driver information measured directly from the driverand the vehicle information measured directly from the vehicle, whereinthe information transfer rate is calculated as a transfer entropy fromthe driver information to the vehicle information; retrieving a baselineinformation transfer rate for maintaining control of the vehicle from abaseline information transfer rate database; and calculating a driversafety factor using the information transfer rate between the driver andthe vehicle and the baseline information transfer rate.
 2. The computerimplemented method of claim 1, wherein the method further comprises:comparing the driver safety factor and a predetermined driver safetyalert threshold; and alerting the driver using a driver alert device ifthe driver safety factor does not exceed the predetermined driver safetyalert threshold.
 3. The computer implemented method of claim 1, whereinmeasuring the driver information directly from the driver includescalculating a driver time series according to the following equation:D _(x) ={d _(x1) ,d _(x2) . . . d _(xN)} where: D_(x) is a time serieswhich is an ordered collection of real values of driver informationmeasured directly from the driver, and d_(x) is a time series segment ofa real value of driver information measured directly from the driver;and wherein measuring the vehicle information directly from the vehicleincludes calculating a vehicle time series according to the followingequation:V _(y) ={v _(y1) ,v _(y2) . . . v _(yN)} where: V_(y) is a time serieswhich is an ordered collection of real values of vehicle informationmeasured directly from the vehicle, and v_(y) is a time series segmentof a real value of vehicle information measured directly from thevehicle.
 4. The computer implemented method of claim 3, wherein theinformation transfer rate between the driver and the vehicle iscalculated using conditional entropies according to the followingequation:T _(D) _(x) _(→V) _(y) =H(v _(yi) |v _(y(i-t)) ^((l)))−H(v _(yi) |v_(y(i-t)) ^((l)) ,d _(x(i-τ)) ^((k))) where: T_(D) _(x) _(→V) _(y) is atransfer entropy from a driver measurement x to a vehicle measurement y,H(v_(yi)|v_(y(i-t)) ^((l))) is the conditional entropy between v_(yi)and a prior segment of V_(y) that is l points long and delayed by tpoints, and H(v_(yi)|v_(y(i-t)) ^((l)),d_(x(i-τ)) ^((k))) is theconditional entropy between v_(i) and a prior segment of V_(y) furtherconditioned on a prior segment of D_(x) that is k points long anddelayed by τ time points.
 5. The computer implemented method of claim 3,wherein parameters t, τ, k, l are adjusted to determine the maximuminformation transfer rate between the driver and vehicle.
 6. Thecomputer implemented method of claim 1, wherein the driver informationmeasured directly from the driver includes at least one of driverbiometric data and direct driver control input device data.
 7. Thecomputer implemented method of claim 1, wherein calculating theinformation transfer rate between the driver and the vehicle includesusing external measurements, wherein the external measurements areobtained using at least one of a camera system, an inter-vehicularcommunication system, or an ultrasonic proximity sensor.
 8. The computerimplemented method of claim 1, further including normalizing theinformation transfer rate between the driver and the vehicle based on atleast one of a type of driver information measured directly from thedriver and driving conditions.
 9. The computer implemented method ofclaim 8, wherein normalizing further includes a GPS of the vehicle beingused to normalize the information transfer rate between the driver andthe vehicle for the type of driver information measured directly fromthe driver and driving conditions, wherein the driving conditionsinclude at least one of a particular road condition, a weathercondition, a time of day, and a traffic condition.
 10. The computerimplemented method of claim 1, wherein the baseline database contains atleast two baseline information transfer rates for the driver, andwherein each of the baseline information transfer rates is for adifferent road condition.
 11. A non-transitory computer-readable storagemedium storing executable code for determining an information transferrate between a driver and a vehicle, the code when executed performs thesteps comprising: measuring driver information directly from the driver;measuring vehicle information directly from the vehicle; calculating aninformation transfer rate between the driver and the vehicle using thedriver information measured directly from the driver and the vehicleinformation measured directly from the vehicle wherein the informationtransfer rate is calculated by comparing a time series of the driverinformation to a time series of the vehicle information; retrieving abaseline information transfer rate for maintaining control of thevehicle from a baseline information transfer rate database; andcalculating a driver safety factor using the information transfer ratebetween the driver and the vehicle and the baseline information transferrate.
 12. The non-transitory computer-readable storage medium of claim11, the code when executed further performs the steps comprising:comparing the driver safety factor and a predetermined driver safetyalert threshold; and alerting the driver using a driver alert device ifthe driver safety factor does not exceed the predetermined driver safetyalert threshold.
 13. The non-transitory computer-readable storage mediumof claim 11, wherein measuring the driver information directly from thedriver includes calculating the time series or the driver information asa driver time series according to the following equation:D _(x) ={d _(x1) ,d _(x2) . . . d _(xN)} where: D_(x) is a time serieswhich is an ordered collection of real values of driver informationmeasured directly from the driver, and d_(x) is a time series segment ofa real value of driver information measured directly from the driver;and wherein measuring the vehicle information directly from the vehicleincludes calculating the time series of the vehicle information as avehicle time series according to the following equation:V _(y) ={v _(y1) ,v _(y2) . . . v _(yN)} where: V_(y) is a time seriesWhich is an ordered collection of real values of vehicle informationmeasured directly from the vehicle, and v_(y) is a time series segmentof a real value of vehicle information measured directly from thevehicle.
 14. The non-transitory computer-readable storage medium ofclaim 13, wherein the information transfer rate between the driver andthe vehicle is calculated using conditional entropies according to thefollowing equation:T _(D) _(x) _(→V) _(y) =H(v _(yi) |v _(y(i-t)) ^((l)))−H(v _(yi) |v_(y(i-t)) ^((l)) ,d _(x(i-τ)) ^((k))) where: T_(D) _(x) _(→V) _(y) is atransfer entropy from a driver measurement x to a vehicle measurement y,H(v_(yi)|v_(y(i-t)) ^((l))) is the conditional entropy between v_(yi)and a prior segment of V_(y) that is l points long and delayed by tpoints, and H(v_(yi)|v_(y(i-t)) ^((l)),d_(x(i-τ)) ^((k))) is theconditional entropy between v_(i) and a prior segment of V_(y) furtherconditioned on a prior segment of D_(x) that is k points long anddelayed by τ time points.
 15. The non-transitory computer-readablestorage medium of claim 11, wherein the driver information measureddirectly from the driver includes at least one of driver biometric dataand direct driver control input device data.
 16. An information transferrate system for determining an information transfer rate between adriver and a vehicle, the system comprising: a computer processor; and acomputer readable storage medium storing executable code when executedby the computer processor performs the steps comprising: measuringdriver information directly from the driver using a driver informationsensing device; measuring driver information directly from the vehicleusing a vehicle information sensing device of the vehicle; calculatingan information transfer rate between the driver and the vehicle usingthe driver information measured directly from the driver and the vehicleinformation measured directly from the vehicle, wherein the informationtransfer rate is calculated using an information transfer rate module ofthe information transfer rate system; retrieving a baseline informationtransfer rate for maintaining control of the vehicle from a baselineinformation transfer rate database of the information transfer ratesystem; and calculating a driver safety factor using the informationtransfer rate between the driver and the vehicle and the baselineinformation transfer rate, wherein the driver safety factor iscalculated using a driver safety factor module of the informationtransfer rate system.
 17. The information transfer rate system of claim16, the code when executed by the computer processor further performsthe steps comprising: comparing the driver safety factor and apredetermined driver safety alert threshold using a driver alert moduleof the information transfer rate system; and alerting the driver using adriver alert device of the vehicle if the driver safety factor does notexceed the predetermined driver safety alert threshold.
 18. Theinformation transfer rate system of claim 16, wherein measuring thedriver information directly from the driver includes calculating adriver time series according to the following equation:D _(x) ={d _(x1) ,d _(x2) . . . d _(xN)} where: D_(x) is a time serieswhich is an ordered collection of real values of driver informationmeasured directly from the driver using the driver information Sensingdevice, and d_(x) is a time series segment of a real value of driverinformation measured directly from the driver using the driverinformation sensing device; and wherein measuring the vehicleinformation directly from the vehicle includes calculating a vehicletime series according to the following equation:V _(y) ={v _(y1) ,v _(y2) . . . v _(yN)} where: V_(y) is a time serieswhich is an ordered collection of real values of vehicle informationmeasured directly from the vehicle using the vehicle information sensingdevice, and v_(y) is a time series segment of a real value of vehicleinformation measured directly from the vehicle using the vehicleinformation sensing device.
 19. The information transfer rate system ofclaim 18, wherein the information transfer rate between the driver andthe vehicle is calculated using conditional entropies according to thefollowing equation:T _(D) _(x) _(→V) _(y) =H(v _(yi) |v _(y(i-t)) ^((l)))−H(v _(yi) |v_(y(i-t)) ^((l)) ,d _(x(i-τ)) ^((k))) where: T_(D) _(x) _(→V) _(y) is atransfer entropy from a driver measurement x to a vehicle measurement y,H(v_(yi)|v_(y(i-t)) ^((l))) is the conditional entropy between v_(yi)and a prior segment of V_(y) that is l points long and delayed by tpoints, and H(v_(yi)|v_(y(i-t)) ^((l)),d_(x(i-τ)) ^((k))) is theconditional entropy between v_(i) and a prior segment of V_(y) furtherconditioned on a prior segment of D_(x) that is k points long anddelayed by τ time points.
 20. The information transfer rate system ofclaim 16, wherein the driver information measured directly from thedriver using the driver information sensing device includes at least oneof driver biometric data and direct driver control input device data.